1. Introduction
In my copending U.S. application Ser. No. 427,277 entitled "Apparatus for the Mounting and Wiring of Printed Circuit Boards", filed Sept. 29, 1982 now U.S. Pat. No. 4,470,101 (the entire disclosure thereof being expressly incorporated hereinto by reference), a novel apparatus was described for the mounting of printed circuit boards in a stacked coaxial relationship relative to one another as conventionally done for components in electrical equipment, e.g. aircraft instrumentation. As fully described in U.S. application Ser. No. 427,277, the invention thereof provides a novel system for the stacked assembly of printed circuit boards which facilitates the eccentric pivotal movement and isolation of selected boards out of the coaxial relationship so as to aid in the manufacture and/or repair thereof.
The present invention is directed to a similar genre of devices in that an apparatus permitting the assembly of printed circuit boards in a stacked relationship is described. More particularly, the present invention is directed to a device which retains printed circuit boards in a stacked relationship transversely between front and rear supports. Although not necessary to the utilization of the present invention, the front support preferably includes an area for the mounting of visual read-out means for instrumentation data, etcetera.
2. Description of the Prior Art
Those in the art to which the present invention pertains have continually sought improved means for contiguously mounting an assembly of printed circuit boards as evidenced, for example, by reference to U.S. Pat. Nos. 4,161,017 to Pierce et al; 3,257,585 to Ransom et al; 3,539,874 to Swanson; 3,596,140 to Walsh and 2,796,559 to Feucht.
Pierce et al disclose a prior art device which permits pivotal movement of printed circuit boards about axes within or parallel to the planes defined by respective circuit boards. Thus, according to the proposal of Pierce et al, if a circuit board located relatively deep in the stack is to be isolated, all circuit boards prior to the desired board must be successively pivoted about their different respective axes to permit unobstructed access thereto. This arrangement is particularly disadvantageous if the circuit board assembly is located in an area of severe spatial limitations. Moreover, since the Pierce et al device contemplates pivotal movement about stacked axes, sufficient slack wire must be provided to permit the extent of pivotal movement necessary for each of the circuit boards in the assembly. It is surmised that upon pivotal movement of the circuit boards, portions of such slack wire may become pinched between the hinge mechanisms or otherwise restrict the intended hinge movements or be exposed to potential damage.
Ransom et al disclose an assemblage of parallel electric or electronic component carrier units. According to Ransom et al, a plurality of component-carrier disc units are attached to a distribution board disk by separate flexible conductive strips radially extending from the distribution board disk, each conductive strip being anchored at one end to the distribution board disk and at the other end to a respective disk.
Swanson discloses that a cradle structure having a plurality of spaced slots can be utilized to hold a stacked arrangement of printed circuit boards. However, as depicted in FIGS. 2 and 3 of the Swanson patent, when predetermined ones of the circuit boards are desired to be removed, they are simply lifted out of the engaging relationship with their associated slot. This form of an arrangement, therefore, utilizes only the interconnecting wiring per se as a means of maintaining the integrity of the assembly when one or more boards are removed from the cradle which could place unnecessary and potentially damaging stresses upon the points of wiring contact with the circuit boards.
Walsh discloses a peripheral contact electronic circuit board assembly. The assembly of Walsh includes a plurality of circuit boards which can be separated from one another by tubular spacers. The circuit boards of Walsh include lugs protruding at regular annular intervals wherein electrical communication can be established between the outside world and the electronic components on the board via contact fingers in contact with conductive rails. Each of the circuit boards and spacers are contained in a cylinder which includes an array of rectilinear T-shaped slots defined in the inner wall parallel to the cylinder axis. Thus, in order to access a circuit board relatively deep in the cylinder, all boards and spacers prior thereto must first be slideably removed from the cylinder.
Feucht discloses that a rigid spacer member can be utilized in combination with a plurality of circuit boards so as to maintain the separation distance therebetween. However, Feucht's main concern is to provide an apparatus permitting the assembly of circuit boards which operates as a heat sink so as to dissipate heat generated by the individual electrical components comprising his assembly.
3. Summary of the Present Invention
As the reader will undoubtedly appreciate from even the most cursory examination of the above prior art proposals, the present invention provides significant advances thereover in both structure and utility in that a circuit board assembly can be provided in accordance with the present invention which facilitates disassembly thereof in the event of repair and/or replacement of any component part yet is of high structural integrity when all component parts are assembled.
Briefly stated, the present invention is directed to the assemblage of printed circuit boards, preferably substantially planar circuit boards, transversely between front and rear supports. The front and rear supports together define substantially aligned front and rear paired mounting slots into which the front and rear portions, respectively, of the printed circuit board are matingly received. Additionally, there is provided according to the present invention a snap ring connector which is seated in a circumferential recess preferably defined by each of the front and rear supports and engageable with indentations formed in circuit boards and mated with the circumferential recess to retain the circuit board in the associated mounting slots to provide overall rigidity to the assembly.
While the present invention is particularly well suited for the transverse mounting of rectangular circuit boards for substantially cylindrically shaped instrumentation, etcetera, the concepts and principles of the present invention could similarly be employed in non-cylindrical instrumentation having circuit boards of other various geometric shapes. Thus, while the accompanying drawings and the detailed discussion thereof below may only describe rectangular printed circuit boards utilized in cylindrical instrumentation, the reader should realize that this merely represents a preferred embodiment in accordance with the present invention and is thus nonlimiting with respect thereto.
It is fairly conventional in the electronic instrumentation art to provide a transformer unit in a contiguous relationship with its associated circuit boards. The present invention also provides a convenient, compact arrangement of a transformer or other electrical components within a bell housing so as to contiguously assemble it with the associated printed circuit boards. The bell housing preferably includes a pair of coaxially disposed gripping fingers which define an annular area with the interior surface of the bell housing into which the transformer is receivable and housed thereby.
To establish electrical communication between the transformer, printed circuit boards and the outside world (e.g. sensors, other instrumentation and the like), an electrical connector is provided which mates with the transformer terminals and preferably defines at least partially arcuate edges which are secured (e.g. by means of solder or the like) to the bell housing. Multi-conductor ribbon connectors matable with printed circuit board terminals are also preferably provided. To complete electrical communication between the operative electrical components of the present invention with outside world, the connector is provided with multiple terminals adapted to matingly engage with a typical plug-in connector. The arcuate edges of the electrical connector closely mate with the interior surfaces of the gripping fingers and in the preferred embodiment of the present invention, are fixed thereto by means of solder or the like.
To complete the assembly of the present invention there is preferably provided an opening concentrically defined in the rear support. The opening includes locking recesses so that upon assemblage of the transformer, electrical connector and bell housing, a portion of the exterior surface of the gripping fingers will mate with respective ones of the locking recesses of the opening so that upon manipulation of the bell housing to effect turning movement thereof relative the rear support (e.g. as by effecting 1/4 turning movement) locking engagement will be effected. In such a manner, all components of the assembly will be maintained in a structurally rigid manner yet will be capable of being quickly and easily disassembled in the event that repair and/or replacement of any component part becomes necessary.
Other advantages and objects of the present invention will become more clear to the reader after careful consideration is given to the detailed discussion relating to the presently preferred exemplary embodiment thereof which follows.